Surgical stapling device and method

ABSTRACT

A surgical stapling device is provided having an elongate housing and a surgical staple slidable longitudinally within the housing towards a free forward end thereof, the staple having a back and two forwardly pointing legs. The housing contains a staple-firing mechanism for driving the staple towards the free end of the housing, bending the staple to bring the free ends of the legs towards one another to close the staple, and releasing the closed staple. A cap is located at the free end of the housing at a position where, in operation of the staple-firing mechanism, the cap becomes trapped between the back of the closed staple and human or animal tissue being stapled so as to provide a greater area of pressure on the tissue than in the absence of the cap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/IE02/00118, filed Aug. 8, 2002, entitled “SurgicalStapling Device and Method,” which designated the United States and waspublished in the English language, and which claims priority to IrelandApplication No. 010748, filed Aug. 9, 2001, entitled “Surgical StaplingDevice and Methods.” These applications are expressly incorporated byreference herein.

This invention relates to a surgical stapling device and method ofsurgical stapling.

BACKGROUND OF THE INVENTION

When performing catheterisation procedures, such as angiography orangioplasty, a catheter is generally introduced into the vascular systemby first penetrating the skin, underlying tissues and blood vessel witha sharpened hollow needle. Next, a guidewire is commonly insertedthrough the lumen of the hollow needle and is caused to enter theselected blood vessel. Subsequently the needle is typically stripped offthe guidewire and the combination of a dilator and/or introducer are fedover the guidewire and pushed through the skin to enter the bloodvessel. The guidewire can then be removed and the desired catheter tocarry out the procedure is fed through the lumen of the introducer andadvanced through the vascular system until the working end of thecatheter is appropriately positioned. Following the conclusion of thecatheterisation procedure the working catheter will be withdrawn andsubsequently the dilator and/or introducer will also be removed from thewound. Following this procedure the vessel puncture must be closed inorder to prevent loss of blood through the puncture hole.

Typically the wound is closed by maintaining external pressure over thevessel until the puncture naturally seals. This procedure can takeapproximately 30 minutes with the length of time usually being greaterif the patient is hypertensive or anticoagulated. The procedure can alsobe uncomfortable for the patient and involves costly professional timeon the part of the hospital staff. Other pressure techniques such aspressure bandages, sand bags or clamps have been employed but these alsoinvolve ensuring the patient remains motionless for the extended periodof time and is monitored to ensure the effectiveness of the procedure.

Therefore there is a need for a device which will close and seal thearterial puncture quickly and easily allowing the patient to becomemobile within a short period of time, thereby increasing the throughputof patients in the catheterisation lab and increasing the availabilityof hospital staff for other duties.

SUMMARY OF THE INVENTION

Accordingly, the invention provides a surgical stapling devicecomprising an elongate housing, a surgical staple slidablelongitudinally within the housing towards a free forward end thereof,the staple having a back and two forwardly pointing legs, astaple-firing mechanism for driving the staple towards the free end ofthe housing, bending the staple to bring the free ends of the legstowards one another to close the staple, and releasing the closedstaple, the stapling device further including a cap located at the freeend of the housing at a position where, in operation of thestaple-firing mechanism, the cap becomes trapped between the back of theclosed staple and human or animal tissue being stapled so as to providea greater area of pressure on the tissue than in the absence of the cap.

Preferably the device further includes an elongated locator memberslidable longitudinally within the housing between an initial forwardposition wherein the locator member projects beyond the free end of thehousing to enter a puncture site in a liquid-carrying vessel in a humanor animal, thereby to locate the free end of the housing at the puncturesite, and a rearward position wherein the locator member is retractedinto the housing in coordination with the closure of the staple, whereinthe cap has a central opening which fits over the projecting locatormember in its initial forward position, the locator member beingwithdrawn from the central opening when it is retracted into thehousing.

Most preferably the closure of the staple effects a lateral compressionof the cap to at least partially close the central opening.

The invention further provides a method of stapling human or animaltissue, the method including providing a stapling device comprising anelongate housing, a surgical staple slidable longitudinally within thehousing towards a free forward end thereof, the staple having a back andtwo forwardly pointing legs, and a staple-firing mechanism for drivingthe staple towards the free end of the housing, bending the staple tobring the free ends of the legs towards one another to close the staple,and releasing the closed staple, the method further including placing acap at the free end of the housing and operating the staple-firingmechanism, the cap being located at a position where, in operation ofthe staple-firing mechanism, the cap becomes trapped between the back ofthe closed staple and human or animal tissue being stapled so as toprovide a greater area of pressure on the tissue than in the absence ofthe cap.

A preferred embodiment of the invention to be described with referenceto the drawings comprises a surgical stapling device as described inIrish Patent Application S2000/0722 in combination with a disk-like cap.The stapling device comprises a handle from which extends an elongatedhousing (shaft). At its end remote from the handle the shaft terminatesin a bullet-like head from which, in an initial “pre-fire” position ofthe device, a locator tube extends a predetermined distance. A surgicalstaple with forwardly pointing legs is located wholly within the head ofthe shaft in the pre-fire position. A generally circular disk having acentral opening is positioned over the locator tube concentric with andflush against the head of the shaft. The diameter of the disk is equalto or less than the diameter of the head of the shaft. On each side ofthe disk generally U-shaped slots are positioned to allow the staplelegs to pass through the disk when they are advanced forward duringdeployment of the staple.

The locator tube locates the head of the shaft centrally over thepuncture hole. On activation of the staple firing mechanism the stapleis advanced forward so that the legs stab the vessel wall. As the firingcycle continues the locator tube is retracted back into the head of thedevice and the staple legs are deformed through 90° in order to form agenerally rectangular shape. Forming the staple causes the disk tobecome trapped between the staple back and vessel wall with additionallateral compression of the two side slots so as to close the centralopening by which the disk was positioned on the locator tube.

The staple and cap combination has the effect of bringing the two sidesof the central opening together and also creating a tamponade effectover an increased surface area so as to bring about haemostasis in ashort time.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a staple and cap combination used in thepresent embodiment;

FIG. 2 is a perspective view of the head end of a surgical staplingdevice according to the present embodiment in a pre-fire position;

FIG. 3 is a side elevation of stapling device of FIG. 2 in the pre-fireposition; and

FIGS. 4( a) and 4(b), FIGS. 5( a) and 5 (b), and FIGS. 6( a) and 6(b)show successive stages in firing a staple into the wall of a bloodvessel using the device of FIG. 2, in which FIGS. 4( a). 5(a) and 6(a)are side elevations of the device and FIGS. 4( b), 5(b) and 6(b) areequivalent plan views of the staple and cap.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIG. 1 shows a preferred surgical staple 10 and cap or cover 12 for usein the embodiment. The staple 10 is a generally U-shaped stapleidentical to that described in Irish Patent Application S2000/0722. Thecap 12 is a generally circular flat deformable disk with a generallyoval central opening 14 and two diametrically opposite generallyU-shaped slots 16 extending radially inwardly from the periphery of thedisk. The dimensions of the oval opening 14 are substantially the sameas the external dimensions of an oval cross-section blood locator tube30 (FIG. 2), and the major axis of the oval opening 14 is substantiallynormal to the direction of closure of the staple legs 22.

The disk 12 is constructed from a soft malleable biocompatible metalsuch as Titanium or a semi-flexible material such as Dacron, Hydrogel,Collagen or Cellulose, or other biocompatible material such as PLA, PGAor PLGA. When the staple 10 is positioned against the disk 12 in use,the hump 18 in the back 20 of the staple is aligned with one half of theoval opening 14 and the staple legs 22 project through the slots 16.

FIG. 2 shows a surgical stapling device according to the embodiment ofthe invention in its “pre-fire” position. Apart from the presence of thedisk 12, the device may be identical to that described in Irish PatentApplication S2000/0722, from which full details may be obtained.Briefly, however, the device comprises an elongate housing or shaft 24extending from a pistol-grip type handle (not shown) and terminating ina bullet-like head 26. The staple 10 is slidable longitudinally withinthe head 26, towards the free forward end 28 of the shaft 24, on a bloodlocator tube 30 slidable longitudinally within, and initially projectingforwardly beyond, the shaft. The legs 22 of the staple point forwardly.In operation, a trigger on the handle operates a staple-firing mechanism(not shown) within the shaft 24 which drives the staple 10 towards thefree end 28, bends the staple to bring the free ends of the legs 22towards one another to close the staple, and finally releases the closedstaple. During this process the blood locator tube 30 is retracted intothe housing in coordination with the closure of the staple.

According to the embodiment, the stapling device further includes thedisk 12 which is located against the free end 28 of the shaft 24 at aposition where, in operation of the staple-firing mechanism, the diskbecomes trapped between the humped back 20 of the closed staple and thehuman or animal tissue being stapled so as to provide a greater area ofpressure on the tissue than would be provided by the back 20 of thestaple alone.

In particular, in the “pre-fire” position of the device, the locatortube 30 extends through the oval opening 14 in the disk 12 and extends apre-determined distance beyond the free end 28 of the shaft. The staple10, while positioned further back in the head 26, is in the same generalalignment with the disk as shown in FIG. 1. However, it is importantthat the staple legs 22 are positioned back in the staple head behindthe disk 12 and not protruding beyond the free end 28 of the staplehead. FIG. 3 is a side elevational view of the stapler head shown inFIG. 2. It can be seen that the staple 10 is positioned across thelocator tube 30 and behind the disk 12 at a distance at least equivalentto the length of the staple legs 22.

The steps involved in firing the staple 10 and disk 12 are illustratedin FIGS. 4 to 6.

First, FIG. 4( a), the stapler head 26 is tracked over a guidewire 32through the percutaneous tract until the front end of the locator tube30 enters a blood vessel 34 providing positive indication that the freeend 28 of the shaft 24 is sitting on the outer surface of the vesseladjacent the puncture hole 36 with the staple and disk positionedcentrally across the puncture hole (see also FIG. 4( b)).

Now the staple-firing mechanism is operated to drive the stapleforwardly such that the staple legs 22 puncture the wall of the vessel34, FIG. 5( a). At this point the locator tube 30 is also beingretracted back into the staple head 26.

Continued operation of the staple-firing mechanism now causes the outerportions of the staple back 20 (i.e. the portions on either side of thehump 18) and the legs 22 to bend through approximately 90° towards oneanother and close the staple 10 to a generally rectangularconfiguration, FIG. 4( c). At this point the staple 10 is compressingthe cap 12 against the outer surface of the vessel wall thereby closingthe puncture hole 36. During the final steps in the deployment processit is important to substantially close the oval opening 14 in the cap toprevent blood from leaking once the staple and cap are deployed. Thus,as seen in FIG. 6( b), as the staple back 20 is deformed, causing thestaple legs 22 to arc through 90°, the opposite edges of the disk 12 arecompressed inwards causing the central oval opening 14 to close.

An alternative embodiment (not shown) of the disk 12 may, instead of theslots 16, have two diametrically opposite holes which do not extend tothe edges of the disk 12. In use these holes are aligned with the staplelegs 22 so that the latter project through the holes.

Furthermore, if the disk 12 is made of a resilient material the ovalopening 14 may be replaced by a simple slit extending substantiallynormal to the direction of closure of the staple legs, the slit beingresiliently forced apart by insertion of the blood locator tube 30 andclosing automatically, by reason of the resilience of the disk, when thetube 30 is retracted. Such an arrangement will not rely on closure ofthe slit by compression by the staple as the latter is deformed.

The invention is not limited to the embodiments described herein whichmay be modified or varied without departing from the scope of theinvention.

1. A surgical stapling device, comprising: an elongate housing; asurgical staple slidable longitudinally within the housing towards afree forward thereof, the staple having a back and two forwardlypointing legs; a staple-firing mechanism for driving the staple towardsthe free end of the housing, bending the staple to bring the free endsof the legs towards one another to close the staple, and releasing theclosed staple; and a cap located at the free end of the housing at aposition where, in operation of the staple-firing mechanism, the capbecomes trapped between the back of the closed staple and human oranimal tissue being stapled so as to provide a greater area of pressureon the tissue than in the absence of the cap, and closure of the stapleeffects a lateral compression of the cap to at least partially close acentral opening formed in the cap.
 2. A device as claimed in claim 1,wherein the free end of the housing has a circular cross-section and thecap is generally in the form of a disk positioned substantiallyconcentrically relative to the free end.
 3. A device as claimed in claim2, wherein the disk has two diametrically opposite apertures foraccommodating the legs of the staple.
 4. A device as claimed in claim 3,wherein the apertures comprise slots extending radially inwards from theperiphery of the disk.
 5. A device as claimed in claim 1, furtherincluding an elongated locator member slidable longitudinally within thehousing between an initial forward position wherein the locator memberprojects beyond the free end of the housing to enter a puncture site ina liquid-carrying vessel in a human or animal, thereby to locate thefree end of the housing at the puncture site, and a rearward positionwherein to locator member is retracted into the housing in coordinationwith the closure of the staple, wherein the central opening in the capfits over the projecting locator member in its initial forward position,the locator member being withdrawn from the central opening when it isretracted into the housing.
 6. A device as claimed in claim 5, whereinthe disk is made of a resilient material and the central opening is aslit extending substantially normal to the direction of closure of thestaple legs, the slit being resiliently forced apart by insertion of theblood locator tube and closing automatically, through the resilience ofthe disk, when the blood locator tube is retracted.
 7. A device asclaimed in claim 5, wherein the central opening is generally oval withits major axis substantially normal to the direction of closure of thestaple legs.
 8. A method of stapling human or animal tissue, the methodincluding: providing a stapling device comprising an elongate housing, asurgical staple slidable longitudinally within the housing towards afree forward end thereof, the staple having a back end two forwardlypointing legs, and a staple-firing mechanism for driving the stapletowards the free end of the housing; bending the staple to bring thefree ends of the legs towards one another to close the staple; releasingthe closed staple; and placing a cap at the free end of the housing andoperating the staple-firing mechanism, the cap being located at aposition where, in operation of the staple-firing mechanism, the capbecomes trapped between the back of the closed staple and human oranimal tissue being stapled so as to provide a greater area of pressureon the tissue than in the absence of the cap.